The deliberate release of Bacillus anthracis spores remains an imminent threat both in terms of bioterrorism and biowarfare. Individuals who inhale these spores are at extreme risk of infection and death from anthrax. Current prophylaxis and therapy in the event of B. anthracis spore inhalation fall into two categories. Vaccination to protect against future exposure, and antibiotic therapy to treat systemic bacterial infections. The commercially available anthrax vaccine requires 6 doses over 18 months for full efficacy and while there have been some non-clinical studies of post exposure vaccination, this has not yet been proven to be helpful for prevention of disease. Antibiotic therapy, usually with ciprofloxacin, is effective only after the inhaled spores germinate and grow as vegetative cells, at which time two anthrax toxins are expressed. It is possible to engineer antibiotic resistant strains of B. anthracis that would render antibiotics ineffective. B. anthracis spores themselves are inert and do not express toxin until they germinate and grow vegetatively, thus it would be of great utility to have a product which could neutralize inhaled spores prior to germination thus keeping them inert until they can be cleared from the body. The lantibiotic peptide nisin has the unique capacity to bind to and neutralize bacterial spores, including B. anthracis spores and spores isolated from antibiotic-resistant B. anthracis. By binding to the spore surface, nisin arrests the germination process. Nisin has received a "Generally Recognized As Safe" designation from the FDA, is currently widely used as a food preservative, and is used in various topical veterinary products. The goal of this submission is to develop an inhaled nisin formulation that could be used in addition to conventional antibiotics and other anthrax therapies in the event of exposure to inhaled anthrax spores. It is the only know intervention that can be used on an emergency basis to neutralize inhaled spores. This product would be deployed with first responders and military personnel in the form of a disposable inhaler to be used immediately after suspected spore inhalation to neutralize the inhaled spores in the lungs prior to germination and toxin production. This proposal will test the capacity of nisin to protect animals against pulmonary challenge with anthrax spores and examine the safety of nisin delivery to the lungs. PUBLIC HEALTH RELEVANCE: Anthrax remains a serious bioterrorism/biowarfare threat. Spores of Bacillus anthracis are relatively easy to produce and disseminate, and the "weaponization" process makes these spores even more effective bioterrorism agents. One of the lessons learned from the events of 2001 is that infections resulting from deliberate exposure to anthrax spores, especially weaponized spores, can be very difficult to treat. In the event of an attack with anthrax spores, victims exposed to the spores can receive several treatments to try to prevent disease progression. The current standard of care is long term dosing of antibiotics like ciprofloxin or doxycycline which can be administered for as long as 60 days. Vaccines, like Biothrax (Emergent Biosolutions) can also be administered immediately after exposure with the hope of generating some protective immunity, but this vaccine requires six doses over eighteen months to be fully protective. Currently, there are no products specifically designed to neutralize spores in the respiratory tract. Anthrax spores are the infectious agent of B. anthracis, but by themselves are inert and not pathogenic. The spores must germinate and grow vegetatively to express toxins, and being able to neutralize inhaled spores in the lungs and prevent their germination could help prevent disease. Optimally, such a neutralizer, which prevent the germination of all spores, but neutralization of even a percentage of the spores would give the other therapies a better chance for success. There is an immediate need for a product specifically designed to neutralize anthrax spores in the respiratory tract. This product should be extremely safe and be able to be formulated in such a way that it can be used in the field in situations and in hospitals where anthrax spore exposure is suspected as an additional layer of protection beyond the use of antibiotics, post exposure vaccinations and other therapies in development. This submission proposes to develop an inhaled product that can neutralize inhaled anthrax spores before they germinate and grow to cause systemic and fatal disease. This product is intended as an addition to other anthrax therapies. Currently there is no such product is available. [unreadable] [unreadable] [unreadable]